The information disclosed in this Background section does not form the prior art and is only for enhancement of understanding of the background of embodiments.
Group 3 to 5 compound semiconductors such as GaN or AlGaN have been widely used for optoelectronics and electronic devices due to many advantages thereof such as wide and easily adjustable band gap energy.
In particular, a light-emitting element such as a light emitting diode or a laser diode using groups 3 to 5 or 2 to 6 compound semiconductor materials of a semiconductor is capable of realizing various colors such as red, green, blue, and ultraviolet by virtue of thin film growth technologies and device materials, is also capable of realizing white light with high efficiency using a fluorescent material or via color combination, and advantageously has low power consumption, semi-permanent lifetime, rapid response speed, safety, and environmental friendliness compared with an existing light source such as a fluorescent lamp or an incandescent lamp.
Accordingly, the light-emitting element has been expansively applied to a transmission module of an optical communication device, a light-emitting diode backlight replacing a cold cathode fluorescent lamp (CCFL) included in a backlight of a liquid crystal display (LCD) display device, a light-emitting diode illumination device replacing a fluorescent lamp or an incandescent lamp, a vehicle headlight, and a traffic light.
With regard to such a light-emitting element, when current is applied thereto, electrostatic discharge (ESD) may occur and, when an amount of ESD is excessive, a defective light-emitting device may be produced and luminous efficiency and optical power of a light-emitting element may be degraded.